Igneous, Metamorphic, And Sedimentary (Mixed Assemblage)

Mixed Rock Collection

Polylithic Geological Specimen Mix

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Beach Pebbles and Quartz Aggregates

Quartz pebbles and biogenic fragments (SiO2, CaCO3)

Gneiss (probable)

Quartz–feldspar–mica gneiss; exact mineral composition cannot be confirmed from the image

Mixed River Stones and Minerals

Mixed Silica-rich Stones (Quartz, Agate, Jasper, Sandstone, Dalmation Stone)

Garnet-bearing amphibolite or mafic gneiss

Amphibolite dominated by hornblende, plagioclase, biotite, and almandine–pyrope garnet

Polished banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Banded River Cobble with Mafic Dike

Hydrothermally altered Graywacke or Sandstone with Mafic Intrusion

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Banded gneiss

Gneiss; typically quartz–feldspar–mica assemblage

Rounded dark stone, likely basalt or weathered mafic rock

Basalt (probable; mineral assemblage commonly plagioclase, pyroxene, and minor olivine)

Polished banded stone, likely gneiss or metasedimentary rock

Banded gneiss (quartz–feldspar–mica assemblage; exact identification requires testing)

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate

Greenschist

Greenschist metamorphic rock (chlorite-epidote-actinolite-albite assemblage)

Quartz-rich pegmatite, with probable feldspar and mica

Granite/pegmatite assemblage: quartz (SiO₂), feldspar (KAlSi₃O₈–NaAlSi₃O₈–CaAl₂Si₂O₈), and mica

Banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Mixed polished river stones

Likely quartz, quartzite, chert/jasper, and possibly limestone or marble

Mixed Rock and Mineral Collection

Various geological specimens

Quartz-rich rock, likely granite or quartz-bearing metamorphic rock

Undetermined; possibly granitic rock composed mainly of quartz and feldspar, with mica or other dark minerals

Small rock fragments; likely mixed local gravel, not identifiable to one species

Unidentified lithic fragments; individual rock types cannot be determined reliably from this photograph

Assorted Decorative Tumbled Stones (Quartz, Sodalite, Aventurine, Calcite)

Mixed Silicates and Carbonates (SiO2, Na8(Al6Si6O24)Cl2, CaCO3)

Mixed collection of quartz-rich rocks and minerals

Quartz (SiO₂), with some pieces possibly containing feldspar or mica; exact identification is uncertain from the image

Dalmation Stone

Peralkaline Rock (mixed silicate minerals)

Banded gneiss

Gneiss, typically quartz–feldspar–mica assemblage

Mixed rock collection

Labeled specimens appear to include iron-rich rock, schist, basalt, serpentinite, and shale

Venetian Gold Granite

Phaneritic Felsic Igneous Rock (Granite)

Mixed gemstone jewelry collection

Various gemstone minerals, including likely amethyst (quartz), sapphire or iolite, garnet, pearl, turquoise, and colored beryl or tourmaline

Quartz-rich granitic cobble

Granite or granitic gneiss; primarily quartz, feldspar, and mica

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Quartz-rich rock fragment

Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image

Mixed collection of common river stones

Varied lithologies, visibly including quartz-rich rock, dark mafic rock, sandstone, and purple quartz-bearing material

Gneiss

Gneiss (High-grade metamorphic rock composed primarily of Quartz, Feldspar, and various Micas)

Mixed small mineral specimens, likely quartz varieties

Uncertain from the image; translucent pieces may be quartz (SiO₂), while golden-brown pieces could be iron-stained quartz or calcite

Weathered quartz-rich pebble

Likely quartz-bearing granitoid or quartz-rich metamorphic rock; exact identification is uncertain from the image

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Quartz and Mixed Minerals

Silicon Dioxide (SiO2)

Mixed Mineral Specimens

Mixed Silicates, Oxides, and Phosphates (SiO₂, Ca₅(PO₄)₃(F,Cl,OH), Na₈Al₆Si₆O₂₄Cl₂, etc.)

Quartz-rich metamorphic rock, likely mica schist

Mica schist; chiefly quartz (SiO₂) and mica, likely muscovite/biotite, with possible feldspar

Granitic Gravel and Soil

Regolith / Alluvial sediment

Greenstone or Epidote-rich rock

Epidote or Chlorite schist/greenstone